Here the 5 Lithics stones:
1) In the south of Route 42, where there are some bushes and rocks, they form a puzzle in Braille. Press the Z key to open the cave. Inside there will be a Lithic Stone in a vessel.
2) On Route 45, follow the path down until you find a locked box with a password. The code is on the stones in the Lithic Forest (6573).
3) At the end of Route 25, there’s another one inside a mailbox.
4) The one from the Pokémon League you should already have.
5) In a house of Saffron City in version 1.0.11+ (before 1.0.11, it was an overly convoluted puzzle).
You can use the stones on Route 45 West.